1. Field of the Invention
The present invention relates to a miter saw having a laser, or other light source, alignment system that uses a beam of light for positioning a saw blade.
2. Background Art
Miter saws are used to cut wood and other materials at precise angles. For example, miter saws are used to cut crown moldings, cove moldings, and other trim pieces and structural members at precise angles. Miter saws generally have a circular blade that is rotated at a high rate of speed to cut workpieces. The blade is guarded by a retractable blade guard that covers the saw blade but is retracted as the blade is brought into contact with a workpiece. The workpiece is generally retained on a supporting table that is adjustable and, in conjunction with a fence, is used to position the workpiece for cutting by the saw blade.
Before cutting, workpieces are generally marked according to precise measurements to assure accuracy. A common problem with miter saws is that it takes a great deal of skill to consistently align the workpiece with the saw blade so that the saw blade cuts at the desired location and at the desired angle. With prior miter saws, it has not been possible to know if the saw alignment is proper until the saw begins to cut the material. If the workpiece is not set up at the correct location with the correct angular orientation, the workpiece may be ruined if it is not properly aligned when the saw blade contacts the workpiece.
A laser arbor for a rotary saw has been proposed in U.S. Pat. No. 5,862,727 to Kelly. The Kelly patent discloses the use of a semiconductor laser arbor for a rotary saw that is actuated by a centrifugal switch and directs a line of laser light on a workpiece. The Kelly patent does not disclose any shielding to prevent the laser from being directed into an operators eyes. Similarly, U.S. Pat. No. 6,035,757 to Caluori et al. discloses a similar semiconductor laser light beam alignment device for a rotary saw having a focusing lens that causes the light beam to be directed to the blade cut line. The Caluori patent likewise fails to disclose any shielding that prevents the laser from shining into an operator's eyes. Both patents also fail to disclose an effective approach to preclude inadvertent operation of the laser when the arbor is disassembled. Furthermore, both patents fail to disclose a system for precisely aligning the laser with the point at which the blade cuts into the workpiece.
An example of a blade guard for a power saw is disclosed in U.S. Pat. No. 5,199,343 to O'Banion. The O'Banion patent discloses a louvered blade guard that an operator can see through while cutting a workpiece. The blade guard has tapered louvers that provide a line-of-sight through a portion of the guard while impeding ejection of cutting debris through the louvers. The O'Banion patent does not disclose or suggest a laser arbor for a rotary saw or any reason to combine the louvered blade guard disclosed with a laser alignment device.
These problems are addressed by the saw having a laser alignment system that includes a laser arbor that rotates with the saw blade on the spindle.